There are various mechanisms in which relatively rotatable members are subjected to thrust loads and also to cocking loads. Typical of such mechanisms are slant axis rotary devices such, for example, as four-cycle, slant axis rotary engines. Such engines may be equipped with thrust bearings of the hydrodynamic type or of the rolling element type.
Oil film thickness in hydrodynamic-type thrust bearings tends to be quite small, usually of the order of a micron or two. Misaligned bearings of this type tend to fail rapidly due to scuffing of the friction surfaces. Bearings of the rolling element type require good alignment to prevent excessive contact stresses from developing due to some rollers carrying more load than others.
The foregoing limitations can be eliminated by building a small amount of flexibility into the bearing supporting structure; but such built-in flexibility unfortunately also permits deflection of the bearing supporting structure producing axial displacement of the center of the bearing.
Axial deflection of slant axis rotary engine thrust bearings is quite harmful because it increases motion of the seals within their grooves and reduces seal life; and in a diesel slant axis rotary engine the motion also reduces the compression ratio.
While the amount of cocking in practice is very small, being only a few minutes of angle, harmful side effects can result in a slant axis rotary engine. Operating on a diesel cycle, the peak pressures are high and the thrust loads are off-center of the rotor and alternate in direction so they first put the shaft in tension and then put it in compression. The eccentricity of the load causes some bending of the shaft, which causes the cocking of the bearing. The severe space limitations require a bearing structure which is axially very compact, but which at the same time is capable of accommodating to cocking action during operation.
The foregoing illustrates limitations of the known prior art. Thus, it is apparent that it would be advantageous to provide an alternative to the prior art.